April 6, 1998 Design News
useful technology for your idea
Digital precision-metering pump
Available in twin or quadruple cylinder
configurations, this precision metering pump offers
large displacement in a compact package.†
A single crankshaft drives two fluid-displacing
pistons, and two cylinders that provide valvless
Designed for precision dispensing of drugs, colorants,
and food additives, this pump's single crankshaft drives
two fluid-displacing pistons, two cylinders, and has
no port valves.
Crankshaft speed and position control provide accurate
volume delivery from zero to maximum speed. Detachable
manifold provides either independent or connected cylinder
channels. Spring-loaded lip seals between pistons and
cylinders, combined with optically flat mating surfaces
between cylinder heads and port plates, result in zero
leakage and fluid "slip by." Other advantages
Near-zero dead volume
Michel Pierrat, Encynova Int'l. Inc.,
557 Burbank St., Broomfield, CO 80020; (303) 404-3583.
The Auto Grab closes and locks as soon as
the headstock hits the top bar, and opens as
guitar is lifted.
Decent guitar stands are usually too big to fit in
a guitar case. The little A-frame ones
that do lack the stability rock n' rollers require
to protect the instrument while jumping around the stage.
This device is basically a mountable latching clamp
that consists of an angle bracket, a keyed receiver
connected to the angle bracket for coupling with the
instrument stand, and a spring latch for securing the
instrument stand in the keyed receiver.
One configuration mounts under the handle of the amp
without any permanent modifications, and the whole thing
folds back out of the way when not in use. The grabber
is available in five different models; most cost between
$24.95 and $39.95.
Big Bang Distribution, 9420 Reseda Blvd.,
Suite 350, Northridge, CA 91324; (800) 547-6401.
Lost motion valve link
Reducing pumping losses during operation at lower engine
speeds increases efficiency. An electrohydraulic valve-train
link uses a solenoid and check valve to modify lift
When solenoid valve is closed, the link is fully expanded.
Slave piston and engine valve follow master-piston and
cam motion. If open, fluid flows from hydraulic circuit
into an accumulator, decreasing link length.
Control module triggers solenoid to modify valve-lift
profile. As camshaft actuates the master piston, it
displaces fluid from its hydraulic chamber to the slave
piston's chamber. Slave piston acts on the valve to
affect delayed valve opening, early valve closing, or
defeat valve motion entirely.
Scott Fowler, Jacobs Vehicle Systems,
22 East Dudley Rd., Bloomfield, CT 06002; (860) 243-7601.
High-resolution magnetic encoder
A proprietary reluctor-wheeland custom ASIC
provide a low-cost,compact-magnetic encoder
that delivers up to 512 cpr.
Magnetic encoders are more durable than optical encoders,
but offer limited resolutions. This compact design uses
a proprietary reluctor-wheel, and a custom ASIC (Application
Specific Integrated Circuit) to achieve up to 512 cpr
(counts per revolution).
A reluctor-wheel, with magnetic domains on its edge
surface, rotates with the motor shaft. Hall elements
pick up flux-density changes as each domain passes by.
The ASIC processes and conditions the encoder signals,
and the resulting position feedback is transmitted to
The dual-channel encoder with digital output is integral
on 15-mm, 22-mm, and 23-mm micromotors. No assembly,
soldering, cable making, or termination additions are
required. Signals are CMOS- and TTL-compatible.
Stephen O'Neil, MicroMo Electronics Inc.,
14881 Evergreen Ave., Clearwater, FL 33762-3008; (813)